{"id":808,"date":"2019-06-14T23:53:29","date_gmt":"2019-06-14T14:53:29","guid":{"rendered":"https:\/\/www.kwonline.org\/memo2\/?p=808"},"modified":"2021-05-25T11:03:00","modified_gmt":"2021-05-25T02:03:00","slug":"spark-scala-sortbykey-descending","status":"publish","type":"post","link":"https:\/\/www.kwonline.org\/memo2\/2019\/06\/14\/spark-scala-sortbykey-descending\/","title":{"rendered":"Spark Scala\u3067sortByKey\u3092\u964d\u9806\u306b\u3059\u308b"},"content":{"rendered":"<p>Spark\u3067reduceByKey\u3057\u305f\u3042\u3068\u306bsortByKey\u3067\u964d\u9806\u306b\u30bd\u30fc\u30c8\u3057\u305f\u304b\u3063\u305f\u306e\u3067\u30e1\u30e2<\/p>\n<p>sortByKey()\u306e\u5f15\u6570\u306bfalse\u3092\u6e21\u3059\u3002<\/p>\n<pre class=\"brush: scala; title: ; notranslate\" title=\"\">\r\nval totalByItem = rdd.reduceByKey((x, y) =&gt;  (x + y)) \/\/\u8981\u7d20\u6bce\u306b\u30ab\u30a6\u30f3\u30c8\u3057\u3066 (\u8981\u7d20, \u500b\u6570)\u306etuple\u306b\u3059\u308b\r\nval flipped = totalByItem.map(x =&gt; (x._2, x._1)) \/\/ tuple\u306e\u8981\u7d20\u3068\u500b\u6570\u3092\u5165\u308c\u66ff\u3048\u3066(\u500b\u6570\uff64 \u8981\u7d20)\u306b\u3059\u308b\r\nval sorted = flipped.sortByKey(false) \/\/ \u964d\u9806\u3067\u30bd\u30fc\u30c8\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Spark\u3067reduceByKey\u3057\u305f\u3042\u3068\u306bsortByKey\u3067\u964d\u9806\u306b\u30bd\u30fc\u30c8\u3057\u305f\u304b\u3063\u305f\u306e\u3067\u30e1\u30e2 sortByKey()\u306e\u5f15\u6570\u306bfalse\u3092\u6e21\u3059\u3002 val totalByItem = rdd.reduceByKey((x, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,9,10],"tags":[],"class_list":["post-808","post","type-post","status-publish","format-standard","hentry","category-data-engineering","category-scala","category-spark"],"_links":{"self":[{"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/posts\/808","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/comments?post=808"}],"version-history":[{"count":1,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/posts\/808\/revisions"}],"predecessor-version":[{"id":1463,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/posts\/808\/revisions\/1463"}],"wp:attachment":[{"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/media?parent=808"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/categories?post=808"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kwonline.org\/memo2\/wp-json\/wp\/v2\/tags?post=808"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}